[21p-212A-1~6] 3.9 Terahertz technologies

△ [21p-212A-6] One dimensional crystal growth mechanism in Ge₂Sb₂Te₅ revealed by strong THz pulse

〇(D)Yasuyuki Sanari¹, Takehiro Tachizaki^2,3, Yuta Saito⁴, Kotaro Makino⁴, Paul Fons⁴, Alexander V. Kolobov⁴, Junji Tominaga⁴, Koichiro Tanaka^3,5, Yoshihiko Kanemitsu¹, Muneaki Hase⁶, Hideki Hirori^1,3 (1.Inst. Chem. Research, Kyoto Univ., 2.Tokai Univ., 3.iCeMS, Kyoto Univ., 4.NeRI, AIST, 5.Kyoto Univ., 6.Tsukuba Univ.)

Keywords:phase change materials, intense terahertz spectroscopy, nonlinear conductivity

We investigated the spatial and temporal dynamics of one dimensional crystal growth that occurs in the phase-change material Ge₂Sb₂Te₅ upon irradiation with an intense terahertz (THz) pulse. THz-pump-optical-probe spectroscopy revealed that Zener tunneling induces a nonlinear increase in the conductivity of the crystalline phase. This result indicates that the large electric field of THz pulses causes a electric field concentration at the edge of the crystallized area. The electric field enhancement in this area induces a temperature increase via Joule heating, which leads to nanometer scale crystal growth parallel to the field direction.